Microfluidic Fabrication of Gelatin‐Nano Hydroxyapatite Scaffolds for Enhanced Control of Pore Size Distribution and Osteogenic Differentiation of Dental Pulp Stem Cells

The combination of gelatin and hydroxyapatite (HA) has emerged as a promising strategy in dental tissue engineering due to its favorable biocompatibility, mechanical properties, and ability to support cellular activities essential for tissue regeneration, rendering them ideal components for hard tissue applications. Besides, precise control over interconnecting porosity is of paramount importance for tissue engineering materials. Conventional methods for creating porous scaffolds frequently encounter difficulties in regulating pore size distribution. This study demonstrates the fabrication of gelatin-nano HA scaffolds with uniform porosity using a T-type junction microfluidic device in a single-step process. Significant improvements in control over the pore size distribution are achieved by regulating the flow parameters, resulting in effective and time-efficient manufacturing comparable in quality to the innovative 3D bioprinting techniques. The overall porosity of the scaffolds exceeded 60%, with a remarkably narrow size distribution. The incorporation of nano-HAinto 3D porous gelatin scaffolds successfully induced osteogenic differentiation in stem cells at both the protein and gene levels, as evidenced by the significant increase in osteocalcin (OCN), an important marker of osteogenic differentiation. The OCN levels are 26 and 43 times higher for gelatin and gelatin-HA scaffolds, respectively, compared to the control group.